Research Of Digital Coordinated Approach To The Civil Aircraft Fuselage Panel Assembly Process Design

Developing the commercial civil aircraft independently is the landmarkundertaking of the “Innovative China Building”. The technical difficulties anddeveloping cycle requirement ate the primary challenges for the local R&D staff.The fuselage components are the major carrying structure of the aircraft. Thecomplexity of the fuselage structure makes the assembly workload reaching40-50%of the entire aircraft manufacturing labor. Moreover, the precision of the fuselagecomponent assembly has an important impact on the aircraft’s aerodynamics designspecifications and structural reliability of the product. Therefore, the primarymission of the assembly process development is finding a scientific and rationalstrategy of the coordination and interchange to guarantee the assembly accuracy ofthe critical product dimensions. The major contents include the work of coordinatedroutes design of assembly, locating datum reference planning and tolerancedistribution of the key characteristics. In the design stage, facing the challenges ofthe huge amount of assembling parts, complicated constraint relations and theintricacy of the deviation transfer processes, designers have to start from referencingthe proven design of sophisticated products which demanding the personalaccumulation of project experience. Multiple rounds of iteration and amendmentsare adapted according to the experimental data of the prototype stage. For thepurpose of development cycle shortening, improving the assembly accuracy andreducing manufacturing risk, the international aviation manufacturer like Boeing andAirbus started to gradually adopt the digital assembly technology since the1980s.The companies achieved significant benefits by using the coordinate digitizingtechniques which become an inevitable trend in the product development of theinternational aviation industry. There is a large gap between China’s aviationindustry and those state of art aircraft manufacturing enterprises in obtaining thehigh accuracy of conformity in design stage and manufacturing process viacoordinating the assembly routes. Transferring from referencing physical standard process equipment to the digital coordinating technique is the feasible solution forour aviation enterprise to satisfy the requirement of civil aircraft development andface to the fierce competition in the international aviation industry.In this thesis, accordance with the characteristics of local civil aircraft designand manufacturing, the research was carried out in the fuselage assembly digitalcoordination and expression of the assembly process and coordination routes. Thetheoretical approach to describe the process digitized coordination, multi-attributedirected liaison graph, was adopted to. Using the mathematic model, the digitaldesign scheme and methods was developed for the fuselage assembly process.Implement of the method in the real engineering case, assembly process design ofcarbine docking and panel component mounting, verified the correctness. Therelated design and manufacturing technical specifications was formed and acceptedby local manufacturing enterprise as the corporate standards. The main contents areas follows.1) The primarily assembly process of the fuselage components mounting wasgeneralized in this dissertation. By researching plenty of the engineeringprojects, dimensional accuracy coordination specifications was developed forthe assembly quality control and process design. The research focused on thedatum reference design and different types of benchmarks of the fuselagecomponent mounting process. By the coordination process researching of thetypical assembly structure, the major influence factors are summarized as thecoordination routes scheme, datum reference switchover and typical approachpattern. The process feature, datum reference feature, positioning precision andmeasurement layout, are assigned to reflect the influence factors of theaccuracy of conformity and standardized as the feature definitions sets.2) The multi-attribute directed liaison graph method is proposed as themathematical expression solution of the fuselage assembly coordinationstructure: restraint characteristics and assembly sequence of the same assemblylayer which expressed in the directed liaison graph can be decomposed into thenodes connection and parts corresponding relationship to reflect the functionaldesign requirement between the different components; the feature definitionsets realize the integrated expression of assembly constructions andcoordination process information; the elicited matrix form the directed liaisongraph are used to automatically coordination route planning for seeking feasible schemes which provides a foundation for the subsequent coordinationoptimization. A cargo door assembly case analysis is enumerated as citedexample.3) A straight fuselage section panel component assembly was set as the analysisobject. Set the key characteristics which according to the functional designrequirement and parts assembly process flow for the influence factor analysis toreveal the coordinative relationship between the parts manufacturing featuresand process scheme planning. Considering the requirements of the geometricand functional constraints of the assembly parts,4feasible coordinativeschemes were simulated via tailor-made assembly variation analysis programfor the multi-objective integrated optimized proposal identification. Themeasurement data of the trials process were compared with the simulationresults to verify the effectiveness of the method.4) Taking the fuselage carbine docking assembly for the object, the segmentassembling digital coordination methods research was carried out in thedissertation. The product design feature, process design separation surface,assembly unit planning specification, positioning reference, et al., wereincluded for the key characteristics control proposal design. By planning thecabin body assembly coordinated multi-attribute directed liaison model, get thepossible coordination programs assign the combinations of tolerance andpositioning reference for viable deviation prediction. The functional tolerancerequirements based segments feature commissioning were utilized in thecoordination optimization. The corresponding design specifications wereformed and adopted in the enterprise applications.The research achievement mentioned is has been successfully applied in theassembly process design of certain commercial aircraft fuselage. Simulation resultsshow the feasibility of fuselage assembly process planning. The implementation ofthe method shows the theoretical value and engineering significance.